This invention relates to assembly of high power semiconductor devices. More particularly it relates to a lead frame-die mount substrate used in such assembly.
High power semiconductor devices are typically made by mounting a semiconductive device die on a heat conductive substrate. Contact areas of the die are interconnected with terminal leads. In the resultant device package, the leads extend outside a housing surrounding the die and interconnections. The leads can initially be part of a lead frame. In some instances, as for example U.S. Pat. No. 3,922,712 Stryker, entitled "Plastic Power Semiconductor Flip Chip Package", issued Nov. 25, l975 to the assignee of this invention, the lead frame and die mount substrate are attached together as a subassembly. They are locked together with the finger leads of the frame and the die mount area on the substrate in alignment. The two can readily be handled as a single element during processing. U.S. Pat. No. 3,922,712 Stryker discloses a particular technique such as this that is useful in manufacturing packages having a flip chip die. Other subassemblies are known for use with dies requiring pressure bonded filamentary wire interconnections.
I have now discovered a new type of subassembly interlock that is particularly useful in making device packages requiring pressure bonding of filamentary wires to thin finger leads of a lead frame.